This is an investigator initiated, randomized, controlled clinical trial. The feasibility, risks, and benefits of intensive insulin therapy in 40 children (6-18 years old) with newly-diagnosed type I diabetes mellitus will be evaluated over a 2 year period. Subjects will be randomly assigned to conventional or intensive insulin therapy. Success of therapy, risk of hypoglycemia, and residual beta-cell function, as measured by C-peptide response to Sustacal, will be evaluated.